Professional SharePoint® 2007 Web Content Management Development: Building Publishing Sites with Office SharePoint Server 2007

6.1. Site Columns

Columns are not new to WSS 3.0, they have been around in SharePoint for a while. However, site columns were introduced in WSS 3.0 in an effort to ease the maintenance of columns in a SharePoint site collection. In WSS 2.0, users could add and edit columns on a list-by-list basis. The challenge with this approach is that it was hard to standardize similar columns across lists. For example, if the field "First Name" was defined in one list as a certain data type, configured to have a minimum length, assigned a user-friendly description and default value, there was no easy way to ensure that other lists containing a "First Name" column conformed to the same specifications. Not only would this cause confusion with end users due to the lack of consistency, but it also created headaches for site owners and administrators to manage the various instances.

To address this, Microsoft introduced site columns, which are reusable column definitions/templates in WSS 3.0 that can be defined once in a SharePoint site and used in different lists in the same site or subsites. These site columns can also be used within content types. While the site columns are defined at the site level, they are available to all child sites of the site they are defined within. Therefore, creating site columns within the top-level site in a site collection effectively creates a site column definition that can be used throughout an entire site collection. All site column definitions are stored in ...